[PATCH AUTOSEL 6.14 498/642] mptcp: pm: userspace: flags: clearer msg if no remote addr

Sasha Levin
2025-05-05T22:34:51Z

From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>

[ Upstream commit 58b21309f97b08b6b9814d1ee1419249eba9ef08 ]

Since its introduction in commit 892f396c8e68 ("mptcp: netlink: issue
MP_PRIO signals from userspace PMs"), it was mandatory to specify the
remote address, because of the 'if (rem->addr.family == AF_UNSPEC)'
check done later one.

In theory, this attribute can be optional, but it sounds better to be
precise to avoid sending the MP_PRIO on the wrong subflow, e.g. if there
are multiple subflows attached to the same local ID. This can be relaxed
later on if there is a need to act on multiple subflows with one
command.

For the moment, the check to see if attr_rem is NULL can be removed,
because mptcp_pm_parse_entry() will do this check as well, no need to do
that differently here.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mptcp/pm_userspace.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 940ca94c88634..cd220742d2493 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -583,11 +583,9 @@ int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info)
if (ret < 0)
goto set_flags_err;

- if (attr_rem) {
- ret = mptcp_pm_parse_entry(attr_rem, info, false, &rem);
- if (ret < 0)
- goto set_flags_err;
- }
+ ret = mptcp_pm_parse_entry(attr_rem, info, false, &rem);
+ if (ret < 0)
+ goto set_flags_err;

if (loc.addr.family == AF_UNSPEC ||
rem.addr.family == AF_UNSPEC) {
--
2.39.5